Apparatus for ejecting articles in cold forming presses or the like

ABSTRACT

A COLD FORMING PRESS WHEREIN THE ARTICLES ARE EXPELLED FROM THE MATRICES BY RECIPROCABLE KNOCKOUT PINS RECEIVING MOTION FROM A RECIPROCABLE CONNECTING ROD OF VARIABLE LENGTH WHICH IS DRIVEN BY A CAM. THE CONNECTION BETWEEN THE KNOCKOUT PINS AND THE CONNECTING ROD COMPRISES A FIRST BELL-CRANK LEVER ONE ARM OF WHICH IS COUPLED TO THE ROD AND THE OTHER ARM OF WHICH IS CONNECTED TO A FIRST LINK IN SUCH A WAY THAT THE AXES OF THE OTHER ARM AND THE FIRST LINK MAKE AN ANGLE OF AT LEAST 150 DEGREES IN THE STARTING POSITION OF THE CONNECTING ROD, A SECOND BELLCRANK LEVER ONE ARM OF WHICH IS COUPLED TO THE FIRST LINK, AND A SECOND LINK WHICH COUPLES THE OTHER ARM OF THE SECOND LEVER WITH A COMMON PUSHER FOR THE KNOCKOUT PINS AND WHOSE AXIS IS AT LEAST NEARLY PARALLEL TO THE AXIS OF KNOCKOUT PINS IN STARTING POSITION OF THE CONNECTING ROD. EACH KNOCKOUT PIN IS ADJUSTABLE AXIALLY WITH REFERENCE TO THE PUSHER.

R. SCHULTE APPARATUS FOR EJECTING' ARTICLES IN COLD FORMING PRESSES OR THE LIKE 5 Sheets-Sheet 1 Filed Oct. 30. 1968 FIGJ 20o INVENTOR March 16, 1971 R. SCHULTE 3,570,300

APPARATUS FOR EJECTING ARTICLES IN COLD FORMING PRESSES OR THE LIKE Filed Oct. 50. 1968 5 Sheets-Sheet 2 INVENTOR /my Own March 16, 1971 R SCHULTE 3,570,300

APPARATUS FOR EJECTING ARTICLES IN 001.1) FORMING PRESSES OR THE LIKE Filed Oct. 50, 1968 3 Sheets-Sheet 5 Hg l/ 13 /"'31 B i it 33 13b INVENTOR film/41y m/47 yV/I/( United States Patent M man Filed Oct. 30, 1968, Ser. No. 771,917 Claims priority, application Germany, Nov. 9, 1967,

K 63,85 Int. Cl. B2ld 45/00; B211 9/18; F16h 21/16 U.S. Cl. 72-427 Claims ABSTRACT OF THE DISCLOSURE A cold forming press wherein the articles are expelled from the matrices by reciprocable knockout pins receiving motion from a reciprocable connecting rod of variable length which is driven by a cam. The connection between the knockout pins and the connecting rod comprises a first bell-crank lever one arm of which is coupled to the rod and the other armof which is connected to a first link in such a way that the axes of the other arm and the first link make an angle of at least 150 degrees in the starting position of the connecting rod, a second bellcrank lever one arm of which is coupled to the first link, and a second link which couples the other arm of the second lever with a common pusher for the knockout pins and whose axis is at least nearly parallel to the axis of knockout pins in starting position of the connecting rod. Each knockout pin is adjustable axially with reference to the pusher.

BACKGROUND OF THE INVENTION The present invention relates to machine tools in general, and more particularly to improvements in cold forming presses or like machines wherein elongated articles which preferably consist of metallic material are shaped by forcing blanks or billets into the cavities of female dies or matrices and wherein the resulting articles must be forcibly expelled from such cavities.

Ejection of articles from the matrices of cold forming presses necessitates the generation of substantial forces, especially when the length of an article exceeds considerably the diameter thereof. In many instances, the knockout pins or ejector pins are actuated by a push rod which is coupled to a bellcrank lever. The latter is provided with a roller tracking a cam which is rotated by the main drive of the press. The pressure between the roller and the cam is very high so that such parts are subjected to excessive wear and must be replaced at frequent intervals.

Another drawback of the just described ejecting apparatus is that the forces transmitted by the knockout pins fluctuate excessively in response to relatively small changes in the strokes of knockout pins. It happens frequently that a relatively small change in the stroke of a knockout pin results in such reduction of ejecting forces that the pin is unable to expel a relatively long article from the cavity of the respective matrix. This is due to the fact that the operative connection between the aforementioned connecting rod and a vertically reciprocable knockout pin normally comprises a wedge which is adjustable in a horizontal plane and which is engaged by a roller follower on the ejector pin. The follower rolls along the inclined face of the wedge and, in order to insure the generation of a reasonably strong ejecting force, the inclination of the face on the wedge must change gradually during a first stage of movement and thereupon becomes more pronounced in order to avoid excessive strokes of the connecting rod. The wedge is subjected to substantial lateral stresses which are transmitted to the knockout pin and, furthermore, the ejecting force decreases very pro- 3,570,300 Patented Mar. 16, 1971 nouncedly in response to relatively small increases in the stroke of the pin, i.e., in response to minor adjustments in the position of the wedge.

SUMMARY OF THE INVENTION It is an object of my invention to provide an apparatus which can eject elongated articles from the matrices or female dies of cold forming presses without subjecting the knockout pins and/or other movable parts to excessive lateral or other stresses, which can furnish a satisfactory ejecting forceieven if the stroke of a knockout pin must be lengthened or shortened within a wide range, and which permits rapid, convenient and simple changes in the stroke of knockout pins, either simultaneously or individually and either to the same extent or to a different extent.

Another object of the invention is to provide an apparatus of the just outlined character which can be built into existing presses without necessitating extensive alterations in the design of such machines.

A further object of the invention is to provide an apparatus which can be utilized to actuate a single knockout pin or two or more knockout pins.

An additional object of the invention is to provide an apparatus which can be operated automatically by the main drive of a cold forming press or the like and wherein all necessary adjustments can be carried out by resorting to simple tools and by employing semiskilled persons.

The apparatus of my invention is used for expulsion of articles from the matrices of cold forming presses or analogous apparatus, particularly for expulsion of elongated metallic articles. It comprises a driving member which preferably constitutes a connecting rod of variable length and is reciprocable between first and second end positions which respectively correspond to retracted and operative positions of a knockout member or ejector member which is arranged to penetrate into or to be withdrawn from the cavity of a matrix, and motion transmitting means connecting the driver member with the knockout member. In accordance with a feature of my invention, the motion transmitting means comprises first and second two-armed levers which are pivotable about parallel axes making right angles with the directions of reciprocation of the driving member and knockout member, a pin articulately coupling one arm of the first lever with one end of the driving member, a first link articulately connecting the other arm of the first lever with one arm of the second lever in such a way that the axes of the link and of the other arm of the first lever make an angle of at least degrees in the first end position of the driving member, and a second link operatively connecting the other arm of the second lever with the knockout member in such a way that the axis of the second link is at least substantially parallel to the axis of the knockout member in the [first end position of the driving member.

The means for reciprocating the driving member preferably comprises a rotary cam which cooperates with a follower provided on one arm of a third two-armed lever whose other arm is coupled to the other end of the driving member. The latters effective length can be regulated by a turnbuckle or the like.

In accordance with another feature of my invention, the operative connection between one or more knockout members and the second link comprises a pusher or ejector bar which is threadedly connected with each knockout member. Means is provided for rotating each knockout member with reference to the pusher to thereby select the initial positions of such knockout members independently of the stroke of the driving member. The rotating means preferably comprises a separate worm drive for each knockout member.

The novel features which are considered as character istic of the invention are set forth in particular in the appended claims. The improved ejecting apparatus itself, however, both as to its construction and its mode of operation, together with additional features and advantages thereof, will be best understood upon perusal of the following detailed description of a specific embodiment with reference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a partly side elevational and partly vertical sectional view of an ejecting apparatus which embodies the invention;

FIG. 2 is a front elevational view of the apparatus as seen in the direction of arrow X in FIG. 1, certain parts of the apparatus being shown in vertical section; and

FIG. 3 is an enlarged substantially horizontal sectional view as seen in the direction of arrows from the line IIIIII of FIG. 1 and showing a slightly different apparatus with several knockout pins.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 illustrates an upright frame member 1 of a cold-forming press for metallic articles. The upper end portion 1a of the frame member 1 supports a rotary camshaft 2 which is rigid with a cam 3 and is rotatable in a clockwise direction. The means for rotating the camshaft 2 derives motion from the main drive (not shown) of the press and includes an intermediate gear 4 mounted in the frame member 1 and meshing with a gear 5 on the camshaft 2. The just mentioned main drive of the press operates the ram (not shown) which in turn cooperates with a female die or matrix M to form enlongated shaped articles of relatively small diameter (as compared to their length). The cam 3 on the camshaft 2 serves to reciprocate a driving member 8, here shown as a connecting rod, by way of a bellcrank lever 6, and the connecting rod 8 serves to operate a motion transmitting linkage which in turn reciprocates a knockout pin or ejector pin 13 serving to expel the articles from the cavity of the matrix M. The lever 6 is pivotable on a pin 5a which is mounted in the frame member 1; the arm 6a of this lever carries a roller follower 7 which tracks the face of the cam 3, and the other arm 6b of the lever 6 is articulately connected with the adjoining upper end of the connecting rod 8 by a pin 7a. The means for biasing the roller follower 7 against the face of the cam 3 comprises two fluid-operated cylinders 11, 11a mounted on the frame member 1 and having downwardly extending piston rods 10, 10a coupled to a crosshead 9 which is affixed to the connecting rod. The pressure of fluid in the upper chambers of cylinders 11, 11a is selected with a view to insure that the roller follower 7 remains in continuous engagement with the cam 3.

The connecting rod 8 is of variable length and comprises two coaxial sections 8a, 8b coupled to each other by a turnbuckle 12 or analogous length adjusting means. Depending on the direction in which the turnbuckle 12 is rotated by the operator or by a mechanism (not shown), the effective length of the connecting rod 8 can be varied within a desired range to insure satisfactory expulsion of shorter or longer articles.

The lower end portion of the connecting rod 8 is articulately connected by a pin 14 to one arm 15a of a bellcrank lever 15 which is turnable on a pivot pin 14S aflixed to the frame member 1 or to another stationary part of the press. The other arm 15b of the lever 15 is coupled to one end of a first link 18 by a pin 17. The other end of this link is coupled to one arm 20a of a further bellcrank lever 20 by a pin 19. The lever 20 is pivotable on a fixed pivot pin 21 and its other arm 20b is coupled to one end of a second link 22 by a pin 23. The other end of the link 22 is coupled to a pusher or ejector bar 25 by a pin 24. The pusher 25 resembles a nut and meshes with the externally threaded lower end portion 130 of the knockout pin 13.

In the embodiment which is illustrated in FIG. 3, the pusher 25 meshes with three knockout pins 13, 13a, 13b. Each knockout pin is turnable with reference to the pusher 25, i.e., each of these pins is provided with a threaded end portion 13c, and each knockout pin is further provided with a pinion 26 which is non-rotatably received in an internally splined sleeve or socket 28 provided in a guide 27 which holds the sleeve against axial movement. Each sleeve 28 is provided with a worm wheel 29 which meshes with one of three worms 30 provided on and rotatable relative to a shift 34. Each worm 30 is rigid or integral with a bevel gear 31 meshing with one of three complementary bevel gears 32 provided on readily accessible spindles 33 shown in FIG. 3. The spindles 33 can rotate the respective bevel gears 32 in a clockwise or in a counterclockwise direction. The parts 2634 constitute a means for rotating the pins 13-13b and for thereby select ing the initial axial positions of these pins independently of each other. As stated before, the spindles 33 are readily accessible so that their exposed polygonal heads can be engaged by a suitable tool to effect appropriate adjustment in the initial position of corresponding knockout pins.

The operation:

FIG. 1 illustrates the first end position or starting position of the connecting rod 8. The camshaft 2 is driven in a clockwise direction and, when the follower 7 engages the lobe of the cam 3, it is caused to assume the phantomline position of FIG. 1 which corresponds to the second end position of the connecting rod 8. The thus displaced follower 7 turns the lever 6 in a counterclockwise direction and the connecting rod 8 moves upwardly against the opposition of cylinders 11, 11a, The unit including the lever 15 and link 18 changes its position to the extent determined by the extent of upward movement of the connecting rod 8. In the first end position of the rod 8, the axes or longitudinal extensions of the arm 15b and link 18 make an angle of almost 180 degrees (see FIG. 1). Moreover, the ratio of the length of arms 26a, 20b of the lever 20 is selected in such a way that the apparatus can produce a very pronounced ejecting force which suflices to effect expulsion of an article from the matrix M. Still further, the pusher 25 is subjected to negligible lateral stresses, mainly because the axis or longitudinal extension of the link 22 is substantially or exactly parallel to the axis of the pin 13 in the first end position of the connecting rod 8. Also, the angular position of the link 22 with reference to the axis of the pin 13 changes very little when the connecting rod 8 is caused to move toward its second end position.

If the working stroke of the knockout pin 13 is to be made longer, the turnbuckle 12 is rotated in a direction to increase the overall length of the connecting rod 8. The relative angular displacement of the arm 15b and link 18 depends on the stroke of the connecting rod 8. However, and in order to insure the generation of a satisfactory ejecting force without unduly increasing the pressure between the roller follower 7 and the face of the cam 3, the angle between the axes of the arm 15b and link 18 preferably at least equals or exceeds degrees. It is further clear that the ratio of the length of the arm 20a to that of the arm 20b can be varied within a certain range.

An important advantage of the just described apparatus is that it can produce highly satisfactory ejecting forces even when the pressure between the roller follower 7 and the face of the cam 3 is relatively low. The force is multiplied by the parts 15, 18, 20 and 22, and such force is transmitted to the knockout pin or pins axially, i.e., with minimal lateral stresses, Another important advantage of the apparatus is that the effective length of ejection strokes of all knockout pins can be varied simultaneously (by changing the effective length of the connecting rod 8) as well as individually by way of the spindles 33. Friction between the relatively movable parts of the motion transmitting means which moves the pusher 25 is much less than between the moving parts of conventional apparatus.

Still another advantage of the improved apparatus is that a single pusher 25 can operate one, two or more knockout pins without being subjected to appreciable lateral stresses. The link 22 is preferably coupled to the pusher 25 in registry with the centrally located knockout pin 13 which is shown as being installed midway between the outer pins 13a and 13b.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features which fairly constitute essential characteristics of the generic and specific aspects of my contribution to the art.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:

1. Apparatus for expulsion of articles from the matrices of cold forming presses or analogous machines, particu larly for expulsion of elongated articles, comprising a driving member reciprocable between first and second end positions; a reciprocable knockout member; and motion transmitting means connecting said driving member with said knockout member so that the latter can expel an article from the associated matrix in response to movement of said driving member from first to second end position, said motion transmitting means comprising first and second two-armed levers, said first lever having one of its arms articulately connected to said driving member, a first link articulately connecting the other arm of said first lever with one arm of said second lever, and a second link providing an operative connection between the other arm of said second lever and said knockout member, the axis of said second link being substantially parallel to the axis of said knockout member in the first end position of said driving member.

2. Apparatus as defined in claim 1, wherein the axes of said other arm of said first lever and of said first link make an angle of at least 150 degrees.

3. Apparatus as defined in claim 1, further comprising means for adjusting the effective length of said driving m m er.-

4. Apparatus as defined in claim 1, further comprising means for reciprocating said driving member including rotary cam means and follower means operatively connected with said driving member and arranged to track said cam means.

5. Apparatus as defined in claim 1, wherein said motion transmitting means further comprises a reciprocable pusher axially adjustably supporting said knockout member and articulately connected with said second link.

6. Apparatus as defined in claim 5, wherein said knockout member is threadedly connected with said pusher.

7. Apparatus as defined in claim 6, further comprising means for rotating said knockout member with reference to said pusher.

8. Apparatus as defined in claim 7, wherein said last mentioned means comprises a rotary sleeve surrounding said knockout member, means provided on said sleeve and said knockout member to hold the latter against rotation with reference to said sleeve, and means for rotating said sleeve.

9. Apparatus as defined in claim 8, wherein the means for rotating said sleeve comprises a worm wheel rigid with the sleeve, a worm meshing with said worm wheel, and means for rotating said worm.

10. Apparatus as defined in claim 9, wherein the means for rotating said worm comprises a first bevel gear rigid with said Worm, a second bevel gear mating with said first bevel gear, and a spindle for rotating said second bevel gear in either direction.

References Cited UNITED STATES PATENTS 3,440,860 4/1969 Byam et a1, 72427 2,546,100 3/ 1951 Johansen et al 72427 2,965,258 12/1960 Wilson 72450 CHARLES W. LANHAM, Primary Examiner R. M. ROGERS, Assistant Examiner US. 01. X.=R. 72-4 5 1; 74-25 

